Among men who seek help for infertility, those who are found to have problems with their sperm - such as a low count or poor motility - are more likely to die in the relatively near future than men with normal sperm, according to a new Stanford study.

The findings, published Thursday in the journal Human Reproduction, suggest that the health of a man's sperm may be tied in important, and hopefully treatable, ways to his overall health. The scientists looked at records of nearly 12,000 men in California and Texas and found that those with sperm defects were twice as likely to die over an eight-year period after being seen for infertility.

The study supports earlier findings that have connected male infertility with long-term health problems such as cancer. But it's among the first to demonstrate an increased risk of death in relatively young men - all of them were between ages 20 and 50 - over a short period of time.

"We've seen other data that there's a link between fertility and long-term health, but the guys I see in my clinic, they're pretty young," said Dr. Michael Eisenberg, director of male reproductive medicine and surgery at Stanford University and lead author of the paper.

"The endpoint, death, usually happens much later in life," Eisenberg said. "It's important to identify this group that's at risk and hopefully prevent these deaths moving forward."

In Eisenberg's study, men who had two or more sperm abnormalities - including low semen volume, low sperm concentration, poor sperm motility and low sperm count - were 2.3 times more likely to die over the study period than men with no abnormalities.

Eisenberg added that it's important to note that the overall risk of death was still very low for the infertile men. Among the 11,935 men studied, only 69 died.

The rate of death - less than 1 percent - for men in the study was actually lower than for the general population over any eight-year period. That may be because men who seek fertility help tend to be wealthier, better educated, and have better access to health care than those who don't seek treatment. All of those factors would result in better health outcomes, including a lower risk of death.

The study doesn't provide many clues as to what the connection between sperm abnormalities and risk of death may be, and it's unclear whether defective sperm might cause health problems or simply be a marker of underlying disease.

Male fertility experts said a combination of genetics, environmental conditions and behavioral choices could explain the association between sperm and health. For example, excessive drinking can cause low sperm counts and also make men more likely to die in a car accident. Also, diseases like diabetes can cause low sperm count as well as increase the risk of heart disease and early death.

Unknown causes

The Stanford study didn't include how the men died - that information was not available in the databases used to cull the information on deaths. But that data will be important to look for in future research, said the authors of the paper and other male fertility experts.

"This is almost like a teaser," said Dr. Keith Jarvi, chief of the division of urology at Mount Sinai Hospital in Toronto, who is familiar with Eisenberg's work. "Because we don't know how these men died, we can't take that next step of using infertility as a means of identifying men who are at higher risk for certain types of problems.

"Right now we don't know if they belonged to the gun and knife club and ended up shot to death."

It shouldn't be surprising that male fertility is tied to all kinds of health outcomes, said Eisenberg and other male infertility experts. Scientists have found that as much as 15 percent of a man's genetic makeup is involved in reproduction. That means if something in a man's DNA is interfering with his fertility, it very likely could be disturbing other important biological processes.

Also, it's possible that the body has developed natural defense mechanisms that make reproduction more difficult when a man isn't otherwise healthy. That could explain why conditions like diabetes or even obesity are associated with poor sperm quality.

"Certainly the body invests a lot in reproduction. If you can't reproduce, there's going to be other consequences," Eisenberg said.

Male fertility experts for the most part said that the study, while fascinating, doesn't provide definitive enough results to suggest that all men get tested for infertility and sperm abnormalities.

Fertility testing?

But on the other hand, they added, men in their 20s, 30s and 40s don't usually see a doctor regularly, and that should change. If questions about infertility and health risks get them to make an appointment, that's not a problem, said Dr. Ajay Nangia, a urology professor at the University of Kansas Medical Center and an expert in male infertility.

"Gynecologists are involved from the time a woman has her first menses. Guys don't have that," Nangia said. "Should all guys be getting semen analysis at 12, 14, 16? That may be overdoing it. But reproductive health is so important to general health. And men need to be much more responsible for their health."